When someone attempts to be cool or do something for another person's entertainment and truly screws up their task into something that results in anger, uncontrollable laughter, or pity to the other person.

<Playing World of Warcraft>

-Guy 1- Dude I'm gonna try and fly all the way to the top of the map and remount before I hit the group, total hxc!

-Guy 2- It's not gonna work...

<Guy 1 falls for 30 sec straight and hits the ground dying on impact>

-Guy who was walking past the road and saw some random person spalt- Epic Fail! ROFL

A naive, lame and immature 16 year old with an ego bigger than Mt. Everest! Tries to act cute and bubbly towards people but is very judgemental and hates on people whom she's never met (in which, she tries to create drama with them via Facebook instead of up front to their face) Also has been known to ruin friendships between best friends by kissing ass to one and rejecting the other, thus resulting in more drama. Has a boyfriend who looks like a mole and creates terrible AMV's.

Person 1: this bitch who i've never even met who is friends with my best friend keeps trying to start shit with me, on facebook!
Person 2: sounds like you have an Epic Fail on your case

ANOTHER EXAMPLE

Person 1: i watched this AMV of Fruits Basket and it was nice except IT WAS TO A FUCKING GLEE SONG
Person 2: lol, did Epic Fail make it?